A – B – C – D – E – F – G – H – I – J – K – L – M – N – O – P – R – S – T – U – V – W – X
| CsF | Caesium formate (coincidentally also an acronym of the sole large-scale supplier of caesium formate brine, cabot specialty fluids.) |
| CALVE | calibrated velocity log data |
| CHDTP | calliper HDT playback log |
| CALI | calliper log |
| CART | cam-actuated running tool (housing running tool) |
| CAPP | Canadian Association of Petroleum Producers |
| CSUG | Canadian Society for Unconventional Gas |
| CSPG | Canadian Society of Petroleum Geologists |
| CART | Cap Replacement Tool |
| CAPEX | Capital expenditure |
| COTP | Captain of the port |
| CCS | Carbon capture and storage (or sequestration) |
| COXY | carbon/oxygen log |
| C&S | cased and suspended |
| CH | Cased hole |
| CSHN | cased-hole neutron log |
| Csg | Casing |
| csg | casing |
| CCL | Casing collar locator |
| CCLP | casing collar locator perforation |
| CCLTP | casing collar locator through tubing plug |
| CHART | Casing hanger assembly running tool |
| CHP | casing hanger pressure (pressure in an annulus as measured at the casing hanger) |
| CHRT | casing hanger running tool |
| CAS | casing log |
| CRT | Casing Running Tool |
| CIBP | cast iron bridge plug |
| CP | Cathodic Protection |
| C&E | Cause and effect |
| CBIL | CBIL log |
| CDIS | CDI synthetic seismic log |
| CE | CE log |
| CECAN | CEC analysis |
| CBL | cement bond log (measurement of casing cement integrity) |
| CEME | cement evaluation |
| CET | cement evaluation tool |
| CERE | cement remedial log |
| CRET | cement retainer setting log |
| CTRAC | cement tracer log |
| API RP 65 | Cementing Shallow Water Flow Zones in Deep Water Wells |
| COS | Center for Offshore Safety |
| cP | Centipoise |
| CATS | Central Area Transmission System |
| CNS | Central North Sea |
| COC | Certificate of Conformance |
| COFR | Certificate of Financial Responsibility |
| CMTR | Certified material test reports |
| CWI | Certified Welding Inspector |
| CGEL | CG EL log |
| CA | Chandeleur Area Gulf of Mexico leasing area |
| CS | Chandeleur Sound Gulf of Mexico leasing area |
| d | Change (delta) |
| CO | change out (ex. from rod equipment to casing equipment) |
| CH | Charlotte Harbor Gulf of Mexico leasing area |
| CHCNC | CHCNC gamma ray casing collar locator |
| CHECK | checkshot and acoustic calibration report |
| CHKSS | checkshot survey log |
| CHKSR | checkshot survey report |
| CDR | Chemical Data Reporting rule |
| CIDL | chemical injection downhole lower |
| CIDU | chemical injection downhole upper |
| CIMV | chemical injection metering valve |
| CIV | chemical injection valve |
| COD | Chemical Oxygen Demand |
| CPI | Chemical process industries |
| CVX | Chevron |
| CFO | Chief financial officer |
| CFC | Chlorofluorocarbon |
| C&K | Choke and kill |
| CBM | choke bridge module |
| CM | choke module |
| XMT | Christmas tree |
| CHROM | chromatolog |
| CST | Chronological Sample Taker log (Schlumberger) |
| CALOG | circumferential acoustic log |
| CRT | Clamp Replacement tool |
| CCA | Clean Carribbean & Americas |
| CGA | Clean Gulf Association |
| CW | Clockwise |
| CITHP | closed-in tubing head pressure (tubing head pressure when the well is shut in) |
| CMR | CMR log |
| CNFDP | CNFD true vertical-depth playback log |
| CNLFD | CNL/FDC log |
| DTPB | CNT true vertical-depth playback log |
| CSG | Coal Seam Gas |
| CBM | Coalbed methane |
| CMP | Coastal Management Program |
| CWPPRA | Coastal Wetlands Protection, Planning & Restoration Act |
| CZMP | Coastal Zone Management Program |
| CFR | Code of Federal Regulations |
| CTLF | coil tubing lift frame |
| CT | Coiled tubing |
| CTCO | coiled tubing clean-out |
| CTD | Coiled tubing drilling |
| CTU | Coiled tubing unit |
| CHOPS | Cold heavy oil production with sand |
| COL | collar log |
| Brent crude | Collection of contracts and futures contracts regarding oil from the Brent, Forties, Oseberg, and Ekofisk fields |
| CSI | Combinable Seismic Imager (VSP) log (Schlumberger) |
| CDP | common depth point (geophysics) |
| CMP | common midpoint (geophysics) |
| CRP | common/central reference point (subsea survey) |
| CGTL | compact gas to liquids (production equipment small enough to fit on a ship) |
| COML | compaction log |
| WAV5 | Compensate Amplitudes |
| CDRCL | compensated dual resistivity cal. log |
| CND | compensated neutron density |
| CNGR | compensated neutron gamma-ray log |
| CNL | compensated neutron log |
| CTLF | compensated tension lift frame |
| CSO | complete seal-off |
| CWOP | complete well on paper |
| CF | completion fluid |
| COMPR | completion program report |
| COMRE | completion record log |
| CWOR | completion work over riser |
| CT | Complex total |
| COMP | composite log |
| COMAN | compositional analysis |
| CAGR | Compound annual growth rate |
| CDP | comprehensive drilling plan |
| CNG | Compressed natural gas |
| P-wave | Compressional wave |
| CFD | Computational fluid dynamics |
| CBT | Computer-based training |
| COMPU | computest report |
| CONDE | condensate analysis report |
| GE | Condensate gas equivalent |
| CGR | condensate gas ratio |
| COA | Conditions of Approval |
| CILD | conduction log |
| CAT | Connector Actuating Tool |
| C/P | Consumption/production (ratio) |
| CONDR | continuous directional log |
| API RP 76 | Contractor Safety Management for Oil & Gas Drilling and Production Operations |
| CHESM | contractor, health, environment and safety management |
| CDU | control distribution unit |
| CRP | control riser platform |
| CBM | conventional buoy mooring |
| CA | core analysis log |
| CORAN | core analysis report |
| CB | core barrel |
| CCHT | core chart log |
| CDATA | core data |
| CD | core description |
| CGL | core gamma log |
| CGPH | core graph log |
| CL | core log |
| CLG | core log and graph |
| COROR | core orientation report |
| CORE | core report |
| CSTAK | core sample taken log |
| CSMT | core sampler tester log |
| CORG | corgun log |
| CORIB | coriband log |
| CSR | Corporate Social Responsibility |
| CC | Corpus Christi Gulf of Mexico leasing area |
| CORLG | correlation log |
| CRA | Corrosion-resistant alloy |
| CPI separator | corrugated plate interceptor |
| CCW | Counterclockwise |
| CPICB | CPI coriband log |
| CPI | CPI log (computer-processed interpretation) |
| CPIRE | CPI report |
| CTOD | crack tip opening displacement |
| CIKR | Critical Infrastructure and key resources |
| XC | Cross-connection, cross correlation |
| X-linked | Cross-linked (to increase gel viscosity) |
| XMAC | Cross-Multipole Array Acoustic log |
| X-over | Crossover |
| XO | Cross-Over |
| XOV | Cross-Over Valve |
| XPOR | Crossplot Porosity |
| XPHLOC | Crossplot Selection for XPHI |
| DSPT | cross-plots log |
| Heavy oil | Crude oil with API gravity of 20 or less |
| Xln | Crystalline (minerals) |
| CSTRE | CST report |
| CRM | Customer relationship management |
| CUT | cutter log |
| CUTTD | cuttings description report |
| CYBD | cyberbond log |
| CYDIP | cyberdip log |
| CYDN | cyberdon log |
| CYBLK | cyberlook log |
| CYPRO | cyberproducts log |
| CSS | Cyclic steam stimulation (method) |