Introduction 1 1. Conventional & Isochronal Tests 5 1. 1 Derivation of Fundamental Flow Equation 6 1. 2 Conventional Test 10 1. 3 Isochronal Test 13 1. 4 Modified Isochronal Test 17 2. Additional Testing Options 23 2. 1 Pseudopressure (Real Gas Potential) Treatment for Gas Flow 24 2. 2 The Radial Diffusivity Equation for Gas Flow 31 2. 3 Analytical Solution of the Diffusivity Equation 33 2. 4 Flow Regimes 34 2. 5 Skin Factor 36 2. 6 Turbulent Flow Factor 40 2. 7 Drawdown or Falloff Test 41 2. 8 Buildup Test 43 2. 9 Determination of S, S' and 0 from Buildup and Drawdown Tests 47 53 3. Additional Testing Considerations 3. 1 Surface-Pressure Relationships 54 Stabilization Time and Radius of Investigation 62 3. 2 Choice of Flow Rates and Duration of Flow Rates 64 3. 3 3. 4 Well bore Storage Effects 65 3. 5 Production of Liquids 66 3. 6 Single-Point Test 68 3. 7 The Orifice Meter 68 3. 8 Testing Equipment 74 76 3. 9 Measurement, Sampling, and Safety in Testing 81 4. Procedures & Regulations 4. 1 Interstate Oil Compact Commission Procedures 83 4. 2 State of Texas Regulations 99 4. 3 State of Oklahoma Regulations 102 4. 4 State of New Mexico Regulations 109 4. 5 State of Louisiana Regulations 123 4. 6 Province of Alberta Regulations 124 vi Gaswell Testing 5. Field Test & Interpretation 127 6.